[PATCH v3 17/25] virtio_blk: enable VQs early on restore

From: Michael S. Tsirkin
Date: Sun Oct 12 2014 - 07:44:54 EST

virtio spec requires drivers to set DRIVER_OK before using VQs.
This is set automatically after restore returns, virtio block violated
this rule on restore by restarting queues, which might in theory
cause the VQ to be used directly within restore.

To fix, call virtio_enable_vqs_early before using starting queues.

Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
drivers/block/virtio_blk.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 46b04bf..1c95af5 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -804,10 +804,13 @@ static int virtblk_restore(struct virtio_device *vdev)
int ret;

ret = init_vq(vdev->priv);
- if (!ret)
- blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
+ if (ret)
+ return ret;
+ virtio_enable_vqs_early(vdev);

- return ret;
+ blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
+ return 0;


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